


Logic Suggests

by nenya_kanadka



Category: Star Trek: Discovery
Genre: Comfort Sex, F/M, Friends With Benefits, Human/Vulcan Friendship, Implied Relationships, Non-Explicit Sex, Non-PIV Sex, Polyamory, Sarek/Amanda OTP, Sleeplessness
Language: English
Status: Completed
Published: 2018-02-18
Updated: 2018-02-18
Packaged: 2019-03-18 23:58:35
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,942
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13692540
Author URL: https://archiveofourown.org/users/nenya_kanadka/pseuds/nenya_kanadka
Summary: "Logic demands that we have sexfor the good of the Federation?"Hell. It's not even the weirdest thing that's happened to her this year.(Kat can't sleep; Sarek offers a tropefic solution.)





	Logic Suggests

**Author's Note:**

  * For [Pixie (magnetgirl)](https://archiveofourown.org/users/magnetgirl/gifts).



> I was originally going to write you Sarek & Philippa, but I couldn't quite make it work. Certainly not better than the "My Michael is better than your Michael" scene canon just gave us. :D But then I remembered our mutual love for Kat Cornwell, and this happened. I hope it's relevant to your interests. <3
> 
> Set during the nine months that _Discovery_ was presumed destroyed and Starfleet is losing to the Klingons.

Kat can't sleep. 

It's not exactly unexpected: Her team was shot in front of her mere hours ago and she's fleeing for her life. A little jitteriness is normal. At least one contact has been compromised, and she and her sole companion have no idea if their route of retreat is as safe as intelligence once suggested or if they're running like hell into another Klingon trap. 

For the last six weeks, instead of operating out of a Starfleet base or even the front lines, Kat has been on an undercover mission. For the last six days, things have been going wrong. For the last six hours, she's been pacing up and down this two-man Vulcan civilian vessel in the middle of an obscure nebula on the edge of Federation space, trying to salvage a tenable plan from the current fiasco. 

Civilian and nebula, because secrecy is of the utmost importance and they are dangerously close to Klingon-occupied territory. Vulcan, because it was the fastest ship they could steal when they made their getaway from their last disastrous rendezvous. She's fairly sure there are scorch marks on the outer hull, and she isn't at all sure of the stability of most of the systems, but the engines are exactly what they were looking for. 

And two-man, because Ambassador Sarek is the last remaining member of her undercover team. 

It is a sign of how disastrously the war effort is going that the only thing that really surprises Kat about any of this is how well the two of them are getting along. 

Sarek the ambassador is famous. Sarek the man she met only after _Discovery_ was destroyed. Both looking for answers, she for Gabriel and Sarek for his daughter, they'd ended up on the same starbase and Kat had been able to tell him how Michael had rescued her from the enemy just hours before her own death. 

She doesn't want to call what's sprung up between them since a friendship, if only because she suspects the Vulcan would find it insulting. But she likes him. They work well together. His suggestions in planning sessions are usually pertinent, he's extremely observant, and he judges Kat's opinions not by how strenuously she argues them but by whether he can follow her logic. It can be a relief, after some grandstanding flag officers she could name. And he's lethal in a physical standoff, which is why Kat's alive right now. 

He's also a Vulcan, which means emotionally unavailable and prone to thinking he's the smartest man in the room, not to mention proud as hell and unwilling to admit it. So if Kat had been asked beforehand, she wouldn't have expected being stuck in close quarters with Sarek to be exactly comfortable. 

But it hasn't felt crowded. 

Her eyes sting with fatigue when Kat closes them, but she can't stop the whirl of thoughts: _what if_ and _who betrayed us_ and the faces of the Starfleet escort who gave their lives this afternoon. Are they being tracked? Sarek thinks not. He quoted a statistical probability to her that wasn't as reassuring as he presumably meant it to be. 

She puts a hand on her diaphragm and breathes in, out, in. She's better at this than she used to be, or at least her professional psychological skills have turned into a hard-won practical arsenal of self-observation, ritual, and distraction in recent months. Ever since the _Sarcophagus_. Theoretically she ought to still be on medical leave, but she's not for the same reason she needs it: the war. 

It's exhausting to be both wounded and healer. 

After a few minutes she feels quieter, but she's still not going to be able to pass out any time soon. Sighing, Kat throws her legs over the edge of the small bunk and yawns her way out of the little sleeping alcove into the shuttle's main navigation chamber. 

The stars shimmer by in the warp bubble outside the ship, the one comforting and familiar thing about their situation. Sarek is standing with his arms tucked behind him, looking out the forward viewscreen. Kat can't quite tell if he's working or meditating, but his head turns at the sound of her footsteps. 

He takes in her wrinkled undershirt and combat trousers, her bare feet and tousled hair. His eyebrows seem to disapprove. "Sixty-seven minutes is an inadequate rest cycle, Admiral," Sarek says mildly. 

Kat sighs and goes to lean against one of the banks of control boards. There don't seem to be any seats on this ship. "Yeah," she says. "I couldn't actually fall asleep. You need any help?" 

It's kind of nice out here. The lights in the nav chamber are dimmed slightly; he had insisted on setting _night_ to match her downtime, which he had likewise insisted she take first, pointing out that he can go without rest longer than she can. 

"Our course will need no adjustments for several hours. I have inventoried the ship's stores and the remains of Lieutenant Robillard's survival kit." He doesn't react to whatever shows on Kat's face at the reminder of their lost team. They only have what was in Kat's pockets and the bag Robillard had handed to Kat right before everything went to hell, so it does make sense to go through it. 

"Thanks." She lets herself slump a little against the console and crosses her arms over her chest. 

"Indeed." He taps a couple of keys on the boards in front of him and then turns to give her his full attention. "You must rest, Admiral. You will need your full faculties shortly." 

Kat shakes her head in frustration. "I've been staring at the ceiling for an hour, and nothing's working." She eyes him. "I don't suppose you found any human-compatible sleeping pills in that inventory." 

"Unfortunately, our medical supplies were in Ensign Tal's care." 

Disintegrated by a blaster bolt. Kat winces. "So that's a no. And I can't risk whatever the ship has on hand." Anything for Vulcans would probably knock her out, but she wouldn't bet on waking up again.

Sarek considers her for a moment. His eyebrow twitches. "I may have a suggestion." 

She scrubs her hand across her eyes. "Sure." At this point she'll stand on her head for ten minutes if it lets her sleep for the next twenty.

"I wish to avoid offence. However, it is logical to ensure that the person on whom I depend for survival is alert when circumstances require." 

"Thanks. I think." Depends on her for survival, Kat thinks. That's...almost like admitting to an emotion. "The feeling's mutual." 

He hesitates. "I am given to understand by she who is my wife that humans and Vulcans share a certain congruence in physiological response." 

Kat holds up a hand. She thinks she knows where this is going, and it's definitely not going to work. "Let me warn you, I'm not that great at meditation." 

"Ah." Sarek tilts his head like he's surprised at that. Then, "I was referring to the lassitude that often follows sexual release." 

"The—oh." She can feel herself colouring. It's essentially _have you tried getting off?_ but Sarek offers it with no undertone of prurient interest. It's like he's asking _have you tried running laps?_ or _what if we turned the heat down?_

Or up. Definitely up. Kat clears her throat. "I haven't really been in the mood. To, uh, make that happen." 

"Would it achieve the required result?" Again the quiet, dispassionate query, somewhere between scientist and monk. He's watching her carefully, but it's not...it's not intrusive. He's working through a problem step by logical step, and he's drawing her along with him. 

"It has in the past," Kat admits. She can't believe she's discussing this with Sarek of all people, but the familiar back and forth of developing a plan with him is strangely calming. "Not usually—" she waves a hand to indicate the general lack of homeliness in the sleek lines of the Vulcan shuttle "—in quite such sterile surroundings." 

There's a pause. "Logic suggests," Sarek says, "that where the environment is foreign, familiarity may be found in known company." 

"True," Kat says, and then plays back the last several seconds. "That sounds like an offer." 

"Logic also suggests that where one participant is insufficient to the task, two may yet succeed." 

Kat blinks. "Logic demands that we fuck?" 

Sarek merely leans against the console and folds his hands in front of him. "Eventually, even I will need to sleep. You must by then be rested. It would be senseless to allow our mission to fail due to human exhaustion when it could so easily be prevented."

"Logic demands that we fuck _for the good of the Federation_?" Kat has a sudden, wild urge to giggle, and claps her hand over her mouth to stifle it. 

Sarek seems unruffled by her outburst, but there is a very, very small glint in his eye. Is he actually _teasing_ her? 

Shit. He is. 

His eyebrow quirks. "Logic would disambiguate between 'fucking' and providing sexual release to aid relaxation." He cocks his head in one of his _doesn't that make perfect sense?_ gestures. "I require no reciprocation." 

"Oh." Kat frowns at him. Technically, he's correct, there's a range of activities under discussion here. There's quite a lot of room between partnered sex and...what, giving her a handjob? (How exactly has a handjob from Ambassador Sarek become a serious option in the last few minutes?) There's still a dozen reasons why this is a bad idea. 

She gets the big one out of the way first: "I assume Amanda would have something to say about all this." 

"Indeed. In the affirmative." 

"I—what?" Kat's eyebrows shoot up. She tends towards open relationships herself, but it's not at all what she's understood regarding conventional Vulcan practices. "In...in general or in specific?" 

He looks at her with the expression she's mentally filed as fond amusement. "My wife has often been concerned for your welfare. She has explicitly commissioned my services in this regard should you ever require them." 

It takes a second to parse that and then Kat buries her face in her hands. Her voice comes out a bit muffled. "So, what, 'get Kat Cornwell laid if you have to do it yourself'?" 

"Essentially." She hears fabric stir against the nav bench as Sarek shifts in place. "It was not an insult, Admiral. Amanda has expressed...interest of her own, as well." 

Oh. That's a thought. That's—she'll think about that one after she's figured out what she's going to do about the first proposal. Kat drops her hands and takes a breath. She can feel the slightly sheepish smile spreading across her face. "I have to say I don't think 'admiral' is appropriate at this juncture." 

"As you wish." 

"Kat's fine." She's still a bit flustered, and the analyst in her is piqued. "So your people usually—"

"Do not divulge our customs as regards interpersonal relations."

Well, that's a resounding _none of your business_ if she's ever heard one. Kat subsides. She stares down at her feet for a minute, thinking it over. She does...trust him. And if she sets aside her initial startlement at the suggestion, she realizes that her body is two steps ahead of her. There's a little stir of interest there. Curiosity. More than a little, if she's honest. Maybe it's just how frank Sarek has been; maybe it's hearing him pronounce the word "fucking." 

She rubs her forehead. Hell. It's not even the weirdest thing that's happened to her this year. 

(She can just imagine Philippa's curiosity about all this. She can absolutely see Gabe's smirk. She hasn't believed in an afterlife in a long time, but maybe somewhere up there the two of them are laughing at her. God knows there's little enough to laugh over anywhere else these days.) 

She stands up and tugs down her undershirt, sets her hands on her hips. "Okay. I'm in. How do you wanna do this?"

He follows her back to the sleeping alcove and settles on the edge of the bunk while she skims out of her trousers. He doesn't kiss, which is...good. But when he trails the tips of his fingers up her bare arm, her skin tingles. Kat lies back on the bunk in her tank top and underwear and isn't quite sure what to do with her hands. 

Sarek clears his throat. "Fantasy is known to be helpful at such times." His hand slides slowly over her clothed stomach. 

"Shut up," Kat grouses, but then she can't stop thinking about what Sarek might consider a good fantasy. Her first thoughts are ridiculous—that he'd get off to a logic problem, or some tangled mathematical equation, or maybe his general sense of superiority to all other species—but then they spiral into warmer, darker, un-Vulcan things. 

By the time he draws the first gasp from her, she's digging her hands into the sheets. Steady heat is pooling in her belly and points south long before he even slides the pads of his fingers under the edge of her shirt. He doesn't really say much, but when her reactions are especially intense or he startles a sudden moan from her, she can tell he notices. He comes back and does it again, usually after just long enough that she thinks he's forgotten. He's building up a repertoire. Very—very logical of him—

"Fuck." Kat grabs his wrist and drags him back to where he's just been. "Yeah. Do that again." 

"My pleasure," Sarek says, very low and a little less composed than normal, and Kat can't help another _fuck_ at that. He's good. He's really...very good. He's obviously had experience with human women and he's obviously paid attention. She wants to ask him if she should send Amanda a thank-you note, but then he drags his knuckles across the front of Kat's underwear and her whole body jerks with a sweet spike of heat. 

"Jesus," she says, when she can breathe. " _Fuck_ , Sarek." 

"Indeed," he says, probably just to make her listen to his rolling, rich voice, the bastard, and then he repeats the motion. Slower, then faster, till her hips are chasing the pressure of his hand. He knows enough now not to stop, and also how to keep her there in that rich, delicious place where she hasn't quite tipped over into ecstasy but her whole body is shivering with little waves of pleasure. 

He was right (the smug, wonderful, Vulcan bastard) about the demands of logic tonight. He was—he—she is going to _hand-write_ a letter and deliver it to Amanda on Vulcan _herself_ , Kat thinks, and she starts to giggle, and she's still laughing when she comes, helpless little snickers interspersed with her moans as she pushes herself against Sarek's hand. 

She might love him a little bit for the fact that he doesn't stop touching her during any of it and that he doesn't say a single goddamn word about how illogical it all is when she's done. 

He's got his palm pressed low against her stomach, grounding her while she comes back to herself. She wipes exhausted (illogical, apparently necessary) tears from the corners of her eyes and heaves a sigh. After a minute or two Sarek gets up from the side of the bed, sweeping the tails of his dark blue coat into order behind him. 

"Thanks," Kat says quietly—a little wobbly still, her face pressed into the too-warm pillow. She reaches for his hand, and he lets her squeeze his fingers, his big palm closing over hers, brief but comforting. 

She can't tell if he's turned on at all, and she thinks it's probably rude to ask. She's glad he said beforehand that he didn't want anything in return, because her eyelids are already starting to close. He tucks the bunk's blanket up around her shoulders, and if he says anything she's too far gone to care. 

Kat sleeps for a solid six hours and is only wakened by the beeping of an alarm on the shuttle's nav computer. It's not loud—tuned for Vulcan hearing—but she's out of the little sleeping alcove and across the shuttle before she remembers that she's still in her underwear.

She shakes her hair out of her eyes and slides to a stop at Sarek's shoulder. "What's happening?" 

"It's the _Vadellan_." Their fallback contact, a Trill vessel with another undercover Starfleet officer aboard. Hopefully a source of much-needed information from behind Klingon lines. Sarek taps a key and brings up their relative positions. Half an hour out. So far, so good. 

Kat takes a breath. "Looks like Captain Farzan's intel was accurate after all." Something's finally going right, she thinks, and quashes the thought. Hope is still dangerous. 

"Yes." Sarek flicks a glance in her direction. "Events are proceeding to plan, Admiral." _It's not an emergency,_ she hears. 

Kat glances down at herself and huffs a laugh. "I'll get dressed." At least the floor's warm under her bare feet. 

"There are still forty-seven minutes until your watch," Sarek says, unperturbed. "I took the initiative to test the coffee program Robillard was carrying. It seems compatible with the ship's replicator."

Kat shakes her head, smiling, as she ducks back into the sleep alcove and tugs on her shirt and trousers. It gives her a minute to stop blushing, and to realize that she doesn't need to in the first place. "Thanks, Ambassador," she calls over her shoulder. 

It looks like this could be the start of a beautiful friendship.

**Author's Note:**

> (As always, [Captain Farzan](http://archiveofourown.org/collections/commodore_paris_in_the_discovery_verse). ;-) One day she'll get actual fic from me.)


End file.
